Gabrielli Alex, Poje Albert B, Manzardo Ann, Butler Merlin G
Departments of Psychiatry & Behavioral Sciences.
Pediatrics, University of Kansas Medical Center, Kansas City, Kansas.
J Rare Disord. 2018 Oct;6(1):18-27.
Prader-Willi syndrome (PWS) is a complex genetic neurodevelopmental disorder with endocrine disturbances, hyperphagia and often life-threatening obesity as key features. We investigated emotional-processing of food and eating behavior in PWS using startle response-modulation. Startle eyeblink response is an involuntary reflex activated by the autonomic nervous system in response to sudden or disturbing auditory/visual stimuli which may be modulated by the emotional valence of concurrently viewed visual stimuli.
Differences in affective modulation of startle reflex were recorded in 13 individuals with PWS versus 8 healthy controls when viewing standard neutral, negative, positive and food-derived images. Electromyogram (EMG) of the orbicularis oculi muscle was measured in response to binaural white noise before and after consumption of a standard 500 Kcal meal. Participants reported their perceived emotional valence for each image, pre- and post-meal, using a 1-10 Likert rating scale.
Subjective ratings of food images and urge to eat were significantly higher in PWS than controls and did not significantly decline post-meal. Acoustic startle responding was detected in PWS but was significantly lower than control participants under all conditions. Startle responses to food images in PWS were attenuated relative to other picture types with potentially abnormal emotional modulation of responses to non-food images which contrasted self-reported picture ratings. A stable positive emotional valence to food images was observed pre- and post-feeding with a sustained urge to consume food in PWS.
Emotional processing measured using startle modulation in response to non-food images was abnormal in PWS which may reflect unique physiological attributes such as hypotonia and abnormal skin conductivity due to increased fat mass. Alternatively, disruption of autonomic or sympathetic nervous system functioning reported in PWS may impact on hunger and/or food drive states. Our findings parallel attentional/processing attributes of affective stimuli reported in autism spectrum disorder and support the feasibility of eyeblink startle modulation to assess food motivation in PWS and provide preliminary data to optimize methodological parameters.
普拉德-威利综合征（PWS）是一种复杂的遗传性神经发育障碍，以内分泌紊乱、食欲亢进和常危及生命的肥胖为主要特征。我们使用惊吓反应调节来研究PWS患者对食物的情绪加工和饮食行为。惊吓眨眼反应是一种由自主神经系统激活的非自主反射，对突然或令人不安的听觉/视觉刺激做出反应，这种反应可能会受到同时观看的视觉刺激的情绪效价的调节。
在13名PWS患者和8名健康对照者观看标准中性、负面、正面和食物来源图像时，记录惊吓反射的情感调节差异。在食用标准的500千卡餐前后，测量眼轮匝肌的肌电图（EMG）以响应双耳白噪声。参与者使用1-10李克特评分量表报告他们在餐前和餐后对每张图像的感知情绪效价。
PWS患者对食物图像的主观评分和进食冲动显著高于对照组，且餐后没有显著下降。在PWS患者中检测到听觉惊吓反应，但在所有条件下均显著低于对照参与者。与其他图片类型相比，PWS患者对食物图像的惊吓反应减弱，对非食物图像的反应可能存在异常的情绪调节，这与自我报告的图片评分形成对比。在PWS患者中，喂食前后对食物图像的稳定正性情绪效价以及持续的进食冲动均被观察到。
使用惊吓调节测量对非食物图像的情绪加工在PWS患者中是异常的，这可能反映了独特的生理特征，如由于脂肪量增加导致的肌张力减退和异常的皮肤导电性。或者，PWS患者中报道的自主神经或交感神经系统功能紊乱可能会影响饥饿和/或食物驱动状态。我们的发现与自闭症谱系障碍中报道的情感刺激的注意力/加工特征相似，并支持眨眼惊吓调节用于评估PWS患者食物动机的可行性，并提供初步数据以优化方法学参数。
